1. Field of the Invention
The invention relates generally to the transfer of data within a computer and more particularly to the control of the transfer of data between multiple processors of a computer.
2. Description of the Related Art
In large computers having multiple central processing units, each CPU typically has an associated service processor. The service processor, for example, initializes the CPU by loading microcode, setting internal latches and activating clocks when the computer is started. Also, service processors often can be used to facilitate diagnostics by keeping a running record of the status of their associated CPUs.
In operation, for example, the multiple service processors of a multiple CPU computer alternatively can operate independently or can operate jointly as a unit. Generally, in order to operate jointly, each service processor needs to have access to computer system information which is available to the others.
For example, when the respective service processors operate independently, they can keep independent running records of the status of their associated CPUs. In order to operate as a unit, however, these independent records often must be made available to each service processor.
Such sharing of information typically involves the transfer of data between the respective service processors. The transfer of such data ordinarily is a relatively routine task. It is desirable that the operating systems of the service processors not be unduly burdened with controlling the transfer of such data.
Thus, there has been a need for an apparatus and method to control the transfer of data between multiple service processors of a computer without unduly burdening the operating system of the service processor. The present invention meets this need.